The prevailing design methodology goals of mobile computing devices (such as smart phones, tablets devices, netbooks, personal data assistants, portable media devices, wearable devices, etc.) is to achieve slimmer profiles while providing ever increasing memory, processing and graphical rendering capabilities, and larger display sizes.
A popular configuration of a mobile computing device includes a main printed circuit board (PCB) having one or more processing elements. These processing elements product heat during operation. However, since the size of the entire device (as a function of a smaller form factor) is limited, less space is available for and between each element. The tighter stack heights and thinner profiles limit the use of conventional thermal control techniques like heat sinks, fans, etc. That not only makes heat dissipation more critical, but also presents additional challenges for heat distribution and dispersal. Moreover, other components (such as camera modules, battery modules, etc.) also generate heat—at least intermittently—during operation.
To address the heat management issue, recently proposed solutions have incorporated materials with phase changing properties for thermal management. Proposed implementations include liquid vapor phase change material in vapor chambers. However, while these chambers are adequate for distributing heat, vapor chambers are less suitable for temporary heat retention, which may be helpful for maintaining consistent operating conditions in a device.